Increased tire size, same psi?

My tires I can’t use the chalk test. So I just went off of the door.

But going from 27psi to 31 made a huge difference in how much truck drives. Well the ride is worse but my mileage and cruising speed is a lot better.

I can’t imagine driving around with 24 psi.

Which brings me to a question with the chalk test. Let’s say you have two tires both pass the chalk test perfectly. But one tire is running 33psi and the other is running 23. Since both pass the chalk test in a similar matter, and let’s pretend they have the same load capacity, will tire B wear out before tire A (assume same compounds too). Meaning is my confusion due to looking at just the pressure or does it not matter if they pass the chalk test?

 

Are you asking, about front to rear bias or 2 different sets of 4 tires?

If the latter...
I can't fathom that ever being a likely scenario. The difference in psi sort of implies they do not have the same load rating and likely they have construction differences associated with diameter, profile, width, etc.
For example:
A euro-metric 110 @ 33 psi=2,183 lbs
A euro-metric 120 @ 23 psi=2,161 lbs
I would expect two such tires to be so different, comparing them is not realistic.

Because Toyota uses a variety of tires, varying in both size and load rating, they also vary in recommended psi. I know in all the 16"-17" sizes, the recommended psi varies from 29-32 psi; yet they all arrive at a 2,149-2,178 lb inflated load capacity. I've never looked into the 18" tires; but I bet it's in that same ballpark.

Either way, chalk or charts, it's ultimately about weight...
MPG or ride comfort is a dumb metric for inflation psi, IMO.
MPGs; you're cheating yourself out of longitudinal footprint, even if chalk shows a good latitudinal footprint.
Comfort; you might be under inflated, cheating yourself of longevity and/or safety.

 

Running my 255/80/17 E rated wildpeaks at 39 front and 37 rear.


Got about 650 of extra weight.

 

Dang! You could probably just replace those with concrete wheels and it would ride the same.

 

Haaaaaaaa!

My buddy drove my truck and said it rides like a chariot.


No complaints from me though.

 

Im all in for the high pressure- I run my 265/75/16 at 38

 

When you say, "...650 of extra weight"; is that on top of curb weight or gvwr. Is it just the gear or does it include the driver?
Your adjusted recommended psi is 36; at least you're in the ballpark.

 

I knew you would chime in. I learned a lot from you regarding tire pressures.

Not including the driver/gear, so on top of curb weight.

80 aspect ratio seem help with a smoother ride.

 

You do bring up something that may change things regarding adjusted recommended psi; increased aspect ratio. Even though you are technically over the adjusted recommended psi, the increased aspect ratio might very well warrant an increase in pressure, to deal with sidewall stability. To handle the dynamics; not so much the increase in weight.
Just shitballin' here...